Telephone-exchange switchboard system.



N0. 693,889. Patented Feb. 25, I902.

W. S. PAGA. TELEPHONE EXCHANGE SWITGHBOABD SYSTEM.

Application filed In. 16, 1901.1

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UNITED STATES WILLIAM S. PAOA, OF ERIE, PENNSYLVANIA, ASSIGNOR OF THREE-FOURTI-IS PATENT OFFICE."

4 TO PETER H. ADAMS AND JOHN Z. MILLER, OF ERIE, PENNSYLVANIA.

TELEPHONE-EXCHANGE SWITCHBOARD SYSTEM.

SPECIFICATION forming part of Letters Patent No. 693,889, dated February 25, 1902.

Application filed March 15, 1901. Serial No. 51,261. (No model.)

To (ZZZ whom it may concern:

Be it known that I, WILLIAM S. PACA, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Telephone-Exchange Switch-- board Systems; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as Will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification;

My invention relates to improvements in telephone exchange switchboard systems; and it consists, substantially, in combining a multiple switchboard with an auxiliary switchboard in such a manner that calls at any section of the multiple switchboard are received at and can also be answered from the auxiliary switchboard.

In multiple switchboards as ordinarily constructed the jacks for connecting subscribers are arranged in sections thereon, and at each section an operator is stationed who answers the calls from and makes the connections for the subscribers whose lines terminate in such section, and necessarily during the busy portions of the day the operators at such sections have great difficulty in answering the calls thereto promptly, as at such times there are frequently several calls in such sections at the same time, and the operator is then obliged to answer the calls and make the necessary connections one at a time, which necessarily causes considerable delay to some of the subscribers so calling the exchange, and

to overcome this difficulty it is frequently necessary to decrease the number of connections in particular sections of the board, as the calls at such sections during the busy part of the day are so frequent that the operator at such section cannot answer them promptly, and in some cases two operators are placed at one section to overcome this difficulty. I entirely overcome this difficulty by means of an auxiliary switchboard, which is so connected up with the main switchboard that one ortwo operators at the auxiliaryboard can at any time promptly assist the operators at busy sections of the main board, so as to avoid delay in promptly answering calls thereto, and when desiredas, for example, at night, when there are comparatively few calls-one or more operators at the auxiliary board can promptly answer all calls coming into the exchange. The construction of a switchboard system by means of which these results are accomplished in what is known as a common-battery telephone-exchange system is hereinafter set forth and described, and illustrated in the accompanying drawings, in which Figure 1 shows a section of a multiple switchboard, an auxiliary switchboard, and line and signal'connections embodying my invention. Fig. 2 is a diagrammatic drawing of line connections, local signal-circuits, and their connections leading to a multiple switchboard and to an auxiliary switchboard embodying my invention.

In the drawings thus illustrating my invention I show an ordinary common-battery system in which the signals at the switchboards are actuated by a common battery which 0perates small electric lights as signals, wherein the common battery is brought into action by the removal of the subscribers receiver from the hook of his telephone.

In Fig. 1, A is a multiple switchboard, and A an auxillary switchboard. B and B are subscribers telephone-stations, and O and O are metallic circuits leading from said telephone-stations to jacks D D and D D on the switchboard A, the jacks D D and D D also'connecting with other circuits 0 and 0 These circuits also lead to jacks d cl on the auxiliaryswitchboard A. E and E are localbattery signal-circuits operatingsignal-lights e e on the main board and e c on the auxiliary board A. In the drawings I have shown only enough circuits and jacks to illustrate a switchboard mechanism of the type hereinafter described embodying my invention, it being well understood thatin a practical switchboard mechanism a number of jacks would be connected with each subscribers circuit, and there would be a jack for each circuit upon each section of the switchboard. The line-wires of each metallic circuit after passing through the contacts F F of a linecut-oft relay F the circuit between them being completed through a battery H and a lamp-signal relay h, through which connection is made with lamp-circuits E and E through a battery H, the lamp-circuits E and E being provided with lamps e and e on the main and auxiliary boards. I and 1 represent a pair of plugs located in each section of the switchboard, it being understood that this pair of plugs and the apparatus shown illustrate the cord-circuits and would be duplicated many times at each section of both switchboards. Across the tip and sleeve conductors J, J, and J of the cord-circuits are bridged divided resistance-coils j j and j j and a supply-battery K. The other apparatus in connection with the cord-circuits will be readily understood when its operation is described, it being necessary to state, however, that the relays L L are contained in the cordcircuits and serve to control the circuits of the relays M M, which in turn serveto control the circuits through the supervisory lampsignals 0 O.

In operation when subscriber B removes his receiver from its hook a current from the battery I-I flows through the line to the signalrelay h and causes the illumination of the lamp 6 on the multiple board A and also the lamp e on the auxiliary board A. The operator at that station seeing the signal inserts the plug I into the jack D on the main switchboard A, or if the operator there is busy the operator at the auxiliary board A inserts her plug I into the jack dthereon, thus in either case connecting the two sides of the line C with the two sides of the cord-circuits. This allows the current from the battery K to flow through the subscribers line C, and this current causes the relay L to attract its armature,and thus complete its circuit through the relay M. The insertion of the plug I forms a circuit from the battery P to conductors J to contact e on the plug I, to the test-thimble Q of the jack D, and by the wire Q, through the relay F to ground G. The current flowing through this circuit accomplishes three purposes-first, the attraction of the armature of the relay M, thus breaking the circuit through the lamp-signal 0; second, the attraction of the double armature of the relay F thus cutting ofi the branches of the line-circuit G beyond the jacks D D and extinguishing the lamps e and e, and, third, the raising of the potential of all the test-thimbles Q connected with that line equal to the drop in the potential through the relay-magnets F so that any operator at another section of the multiple board A or at the auxiliary board A attempting to make a connection with this line would be warned upon touching the tip of the plug to thetest-thimble that the line was busy by a click in her head-receiver. Upon learning the connection desired by the subscriber the operator applies the tip of the plug 1 to the testthimble of the jack connected with the line of the party calledfor, and if she hears no click in her head-receiver the line is not in use, and she thereupon inserts the plug I into the jack, upon which the current from the battery P will pass through the lamp-signal 0, through the rearward sleeve of the plug, and by the test-thimble to the line-cut-oii rclay F of the called subscribers line C to ground G. This illuminates the lamp 0 and operates the cut-ofi relay F as before. The lamp 0 remains lighted until the subscriber B responds to the call,when upon the removal of his receiver from its hook the current from the battery K is allowed to flow through his line. This operates the relay L, energizing relay 1 and thus extinguishes the lamp 0, at the same time allowing enough of the current to flow through the magnet M to serve for testing purposes and hold the relay F closed. The subscribers now converse in the usual manner, and when either of them hangs up his receiver the circuit through that line is broken and the corresponding relay L or L, as the case may be, and releases its armature. This deenergizes the relay M or M and causes the signal-lamp O or O to become lighted as a signal for disconnection, and upon removing the plugs from the jacks all apparatus is restored to its normal condition.

In the circuits with the lamps O and 0 there is a relay-magnet R controlling the current of a pilot-lamp S, having a battery 3, which pilot-lamp S is common to the group of plugs controlled by any one operator. This lamp is placed either at a conspicuous place on the switchboard or upon a chief operators switchboard and serves to indicate whether the operator to whose section the lamp S belongs is properly attending to clearing-out signals.

It will be understood that I have described one type of what is known as a commonbattery signal system for multiple switchboards and that the mechanism hereinbefore described is also duplicated at the auxiliary switchboard, which is connected with the circuits leading to the main board by means of circuits illustrated by the lines E E and C C Q Q By means of these connections every signal sent to any section of the main board is duplicated at the auxiliary board, and the operator at the auxiliary board can answer and connect up any subscribers connected with the main board with the same facility as can be done by the operator or operators at the main board.

In describing, as I have hereinbefore done, a type of common-battery signaling mechanism which can be utilized in the construction and operation of my invention I do not limit myself to the use of this system, as I can read ily utilize any common-battery signaling sys term in the construction and operation of my invention, which consists, not in the particular system used, but in the combination of an auxiliary switchboard with a main multiple switchboard in such a manner that an op- -erator at any section of the main board can be assisted by an operator at the auxiliary board without in any manner disturbing or inconveniencing the operator at such main switchboard.

Therefore, having described my invention, so as to enable others to construct and use the same, what I claim as new, and desire to secure by Letters Patent of the United States, is-

1. In a telephone-exchange switchboard system, the combination of a main multiple switchboard, subscribers and signal circuits leading into said main switchboard, an auxiliary switchboard, and circuits connecting the subscribers and signal circuits at the main switchboard with the auxiliary switchboard, substantially as and for the purpose set forth.

2. In a telephone-exchange switchboard system, the combination of a multiple switchboard, a common-battery signal mechanism at said switchboard, subscribers circuits leading to said main switchboard and said signal mechanism, an auxiliary switchboard, and

circuits connecting the subscribers and signal circuits at the main switchboard, with said auxiliary switchboard, substantially as and for the purpose set forth.

3. In a telephone-exchange switchboard system, the combination of a main multiple switchboard, jacks and operators circuits, a common-battery signal mechanism, circuits connecting subscribers circuits with said signal mechanism and with the jacks and operators circuits on said main switchboard, an

auxiliary switchboard, a common-battery sig- 

